典型规模化养猪场废水中兽用抗生素污染特征与去除效率研究

采用固相萃取结合高效液相色谱/串联质谱方法,对苕溪流域某规模化养猪场排放的典型废水进行兽用抗生素污染检测.结果表明,废水中四环素、土霉素、金霉素和强力霉素等4种四环素类抗生素污染最为严重,最高单体污染浓度可达13.65×103ng·L-1.磺胺嘧啶、磺胺甲唑和磺胺二甲嘧啶等3种磺胺类物质也有一定的检出量,但以磺胺二甲嘧啶较为突出,最高检出量为675.4ng·L-1.氧氟沙星以及红霉素和罗红霉素等喹诺酮和大环内酯类抗生素除了原水有较低的检出量,其它废水均未检出.厌氧消化废水处理系统对废水中高浓度的抗生素具有明显的去除效果,但对低浓度的抗生素去除率较低.与欧盟水环境抗生素阈值(10ng·L-1)相比,排放水中的抗生素污染浓度对周边地表水环境的污染风险仍需要引起重视.通过饲料摄入途径估算养猪场排泄物抗生素含量,并与实测值比较,结果表明,饲料摄入并不是该养猪场兽用抗生素利用的主要方式,可能存在其它用药途径,需要在今后的畜禽养殖兽用抗生素的污染调查、风险估算和消减工艺研发中引起重视.

A preliminary study on the occurrence and dissipation of antibiotics in swine wastewater

The occurrence and dissipation of the following 11 selected antibiotics were studied in swine wastewater at one large animal feeding operation (AFO) using HPLC/MS/MS: tetracycline (TC), oxytetracycline (OTC), chlortetracycline (CTC), doxycycline (DXC), sulfadiazine (SD), sulfamethoxazole (SMT), sulfamethazine (SMX), norfloxacin (NFC), ofloxacin (OFC), erythromycin-H2O (ETM-H2O), and roxithromycin (RTM). The wastewater samples were unavoidably contaminated with antibiotics and the main contaminants were TC, OTC, CTC and DXC, with maximum concentrations of individual contaminants reaching 13.65×103 ng·L-1. The sulfonamides (SD, SMX and SMT) were also present in measurable concentrations, with a maximum value of 675.4 ng·L-1 for SMT. OFC, ETM-H2O and RTM were observed in the raw wastewater only. Anaerobic digestion technology can significantly degrade the contaminants but showed low efficiencies of dissipation of other analytes at lower levels of contamination. On the basis of the European Union trigger value (10 ng·L-1), effluent water from this wastewater treatment system may pose risks to the aquatic environment in the vicinity of the swine farm because of the antibiotics present at higher concentrations. It is important to compare the actual concentrations of veterinary antibiotics in wastewater produced by this farm and the predicted concentrations calculated on the basis of detection in the animal feeds used. Greater attention must be given to the pattern of use of medicines on the farm, including environmental risk assessment and research on the mitigation of antibiotic contaminants.